Simultaneously Broadened Visible Light Absorption and Boosted Intersystem Crossing in Platinum-Doped Graphite Carbon Nitride for Enhanced Photosensitization

Herein, taking graphite carbon nitride ( g -C 3 N 4 ) as the example, we demonstrated that the two limiting factors that determine the photosensitization performance, namely, light absorption and intersystem crossing (ISC), could be simultaneously enhanced through Pt 2+ doping. Specifically, as a π-conjugated two-dimensional semiconductor, g -C 3 N 4 is capable of absorbing light shorter than 460 nm (2.7 eV). Upon Pt 2+ doping that allows metal-to-ligand charge transfer (MLCT) from Pt 2+ to the substrate g -C 3 N 4, the light absorption of g -C 3 N 4 was greatly expanded up to 1000 nm. Meanwhile, the large atomic number of Pt 2+ ensures promotion of ISC to activate the triplet state of g -C 3 N 4 via heavy atom effect (HAE), which was confirmed via both photosensitization performance and photophysical characterizations. Further, the enhanced light absorption and photosensitization of Pt 2+ -doped g -C 3 N 4 were harvested for antibiotics removal, a type of environment contaminants that gained global attention because of their worldwide abuse. Compared with its undoped counterpart, Pt 2+ -doped g -C 3 N 4 featured significantly improved antibiotics removal in the presence of low-power white LED irradiation, which is promising for photosensitized environmental remediation.